CVE-2022-20946: Cisco Secure Firewall Threat Defense

High severity, CVSS 7.5. EPSS: 0.9% chance of exploitation in the next 30 days.

A vulnerability in the generic routing encapsulation (GRE) tunnel decapsulation feature of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to a memory handling error that occurs when GRE traffic is processed. An attacker could exploit this vulnerability by sending a crafted GRE payload through an affected device. A successful exploit could allow the attacker to cause the device to restart, resulting in a DoS condition. https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-gre-dos-hmedHQPM ["https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-gre-dos-hmedHQPM"] This advisory is part of the November 2022 release of the Cisco ASA, FTD, and FMC Security Advisory Bundled publication.

Affected products

• Cisco Secure Firewall Threat Defense: from 6.3.0, up to and including 6.3.0.5; from 6.4.0, up to and including 6.4.0.15; from 6.5.0, up to and including 6.5.0.5; from 6.6.0, up to and including 6.6.5.2; from 6.7.0, up to and including 6.7.0.3; from 7.0.0, up to and including 7.0.3; …

Published 2022-11-15. Last modified 2026-08-11.